I have a 64 impala and would like to know what backspacing you would need for rims 15 -20 inches not to rub. I have tried to put a 15 inch rim on 275/60's in the back and I didnt even get close. I'm sure that you can fit a least that size. Could anyone tell me what they are currently running rim and wheel wise on their 64 Impala and/or any rim/tire combinations that fit well on that year? Thanks very much.